In process automation technology, field devices are often applied to serve for registering and/or influencing process variables. Sensors such as, for example, fill level measuring devices, flow measuring devices, pressure and temperature measuring devices, pH-redox potential measuring devices, conductivity measuring devices, etc. serve for registering the corresponding process variables, fill level, flow, pressure, temperature, pH value, and conductivity, respectively. Actuators such as, for example, valves or pumps, via which the flow of a liquid in a pipeline section or the fill level in a container can be changed, serve for influencing process variables. In principle, all devices, which are applied near to the process and deliver or process information relevant to the process, are referred to as field devices. A large number of such field devices are available from the firm, Endress+Hauser.
In modern industrial plants, field devices are, as a rule, connected via bus systems (Profibus®, Foundation® Fieldbus, HART®, etc.) to superordinated units. Normally the superordinated units are control systems or control units, such as, for example, a PLC (programmable logic controller). Among other things, the superordinated units serve for process control, process visualizing, process monitoring as well as for the start up of field devices.
In the start up of a plant, a superordinated unit performs the system configuration by means of an engineering program (engineering software), which is loaded into the superordinated unit. In such case, the superordinated unit especially performs the configuration of the individual field devices associated with the superordinated unit. In such a configuration, among other things, it is determined, which outputs the superordinated unit provides to the individual field devices associated with the superordinated unit in the context of process control and which inputs are obtained by the superordinated unit from the individual field devices associated with the superordinated unit in the context of process control.
Computer supported systems, through which asset management, state monitoring (condition monitoring), and/or plant monitoring are performed, are frequently applied in plants using process automation technology. Such systems are often embodied separately from a superordinated unit, which, among other things, serves in a fieldbus segment for process control. Frequently, they are connected to a superordinated (to the fieldbus segment) company network (for example, an Ethernet® network). In this way, these systems can be comprehensively applied for a number of fieldbus segments.
Such systems often require, for the execution of their services, configuration information relative to the cyclic data traffic on each fieldbus. For example, configuration information relative to the cyclic data traffic of each fieldbus is required, in order to be able to evaluate telegrams, which in the context of process control, are transmitted via the fieldbus between a superordinated unit and at least one field device associated with the superordinated unit. In such case, it is problematic that the computer supported systems described above, when these are embodied separately from a superordinated unit (e.g. a PLC), often have no access to the required configuration information relative to the cyclic data traffic on the fieldbus. This is especially the case when the computer supported systems are from a manufacturer different from the manufacturer of each superordinated unit.
A method for monitoring a plant, in which a number of field devices communicate via a fieldbus with a process control unit and a plant monitoring unit, such as, for example, a gateway, is known from WO 2007/074105 A2. The plant monitoring unit checks, in such case, the regular data traffic for information indicating a diagnostic event in one of the field devices. If a telegram with an indication of a diagnostic event is detected, other diagnostic information of the relevant field device is requested by the plant monitoring unit.